1. Field of the Invention
The present invention relates to hinge technology, and more particularly to an improved structure of planetary type dual-shaft hinge, which provides a variable radius in a flip-up electronic device by using a female shaft to match with two male shafts so that when the cover member of the flip-up electronic device is opened from the base member thereof, the female shaft and the male shafts are rotated to smoothen the pivoting motion of the cover member, enabling the cover member and base member of the flip-up electronic device to be kept on one same plane after the flip-up electronic device is fully opened.
2. Description of the Related Art
Hinges are intensively used in flip-up mobile electronic devices such as notebooks, smart phones, and etc. to pivotally connect a base member and a cover member together, allowing only a limited angle of rotation between them. Some flip-up mobile electronic devices allow the cover member to be turned from the top side of the base member to the bottom side thereof, enabling the flip-up mobile electronic devices to be used as a tablet computer.
A hinge for this application is a dual-shaft design. Taiwan Patent Publication Number M413776 discloses a dual-shaft hinge design. According to this design, first coupling means and second coupling means are provided at two opposite sides of connection plate means; the first coupling means provides a first opening at an end edge thereof adjacent to one side of connection plate means; the second coupling means provides a second opening at an end edge thereof adjacent to an opposite side of connection plate means; a first male shaft and a second male shaft are respectively mounted in the first coupling means and the second coupling means. When opening a cover member from a base member of a flip-up electronic device using the hinge, the first male shaft and the second male shaft are rotated one after another in a proper order, allowing the cover member to be easily lifted with less effort. However, when reversing the cover member relative to the base member to close the flip-up electronic device, mush resisting force will be produced. According to this conventional design, the first coupling means and the second coupling means can wear quickly with use, resulting in elastic fatigue losing and losing their functions to rotate in sequence.